Year	Percent
1973-01-01	18.1654
1974-01-01	19.5978
1975-01-01	21.4954
1976-01-01	21.9089
1977-01-01	23.2466
1978-01-01	24.1334
1979-01-01	23.7958
1980-01-01	23.8253
1981-01-01	23.2708
1982-01-01	25.0464
1983-01-01	27.6032
1984-01-01	29.1673
1985-01-01	29.4802
1986-01-01	31.7045
1987-01-01	32.4933
1988-01-01	31.5472
1989-01-01	30.5126
1990-01-01	27.9064
1991-01-01	24.9602
1992-01-01	23.6693
1993-01-01	22.3580
1994-01-01	20.9435
1995-01-01	19.8537
1996-01-01	19.7851
1997-01-01	22.9508
1998-01-01	27.9354
1999-01-01	32.2764
2000-01-01	32.7527
2001-01-01	34.4811
2002-01-01	35.4958
2003-01-01	35.5836
2004-01-01	36.2131
2005-01-01	37.4082
2006-01-01	41.0047
2007-01-01	47.2356
2008-01-01	51.4897
2009-01-01	52.6966
2010-01-01	50.7456
2011-01-01	49.6121
2012-01-01	53.0146
2013-01-01	58.2684
2014-01-01	59.5641
2015-01-01	59.2885
2016-01-01	60.4044